The present invention is in the field of off-road recreational vehicles and pertains more particularly to methods and apparatus for stabilizing maneuverability of an off-road vehicle such as a snow mobile and improving balance and leveraging capability for a user operating such a vehicle.
Two of the more popular off-road recreational vehicles are the all-terrain-vehicle (ATV) and the snowmobile. There are obvious differences in the types of terrain where these vehicles are used, which is evident in the differences in their constructions. For example, a snowmobile is a rear-tracked vehicle with two front skis adapted for maneuvering over various types or conditions of snow-pack. An ATV is typically a motor-driven, four-wheeled vehicle adapted for maneuvering over rough, muddy or sandy terrain.
In spite of obvious differences in method of propulsion and types of terrain traveled, there are a few commonalties between these two types of off-road vehicles. A major similarity is in the method and apparatus used in steering, throttle control, and breaking apparatus of such vehicles. For example, both types of vehicles support crossbar handles wherein a throttle control typically is placed near the end of the right bar of the handlebar and a vehicle breaking control typically is near the end of the left bar of the handlebar. The cross-configuration of the handlebar and the location of both throttle control and breaking control is consistent with supporting the type of maneuvering required in the operation and control of these otherwise very different vehicles.
Both of the above-described vehicles support column steering apparatus connected to front steering members. For a snowmobile, the front steering member acts to steer the skis. In an ATV, the front steering member acts to control the front wheels. Breaking acts to slow or stop the rear track of a snowmobile, while slowing or stopping the rear wheels of an ATV.
Another similarity between the above-described vehicles is that both support running boards or platforms located on either side of their chassis for the purpose of allowing a user to dismount from the seat area and to stand on a side running board for balance and weight shifting purposes during certain steering maneuvers. A maneuver common to both ATVs and snowmobiles, wherein standing on a side or running board is applicable, is termed side-hilling in the art. Side-hilling involves maneuvering the vehicle laterally across sloping terrain in either direction lateral to the slope without having the vehicle inadvertently turn downward toward the direction of the slope against the intent of a user.
A common problem associated with side-hilling is that both ATVs and snowmobiles naturally lend to turning downhill against the wishes of a user due to forces of gravity which take into account the weight of the vehicle (approx. 600 lbs.) and, the angle of the slope. The problem becomes more acute at greater angles of slope. In an attempt to off-set this down hill tendency, a user typically stands on the uphill-side running-board to obtain a shift of weight to the uphill side, which acts to reduce the chance of roll-over and reduces muscle strain on a user attempting to hold a slight upward steering position with respect to the position of the handlebars.
Particularly with snowmobiling, which will be the main focus of this specification hereinafter, it is more difficult to side-hill in the direction in which the hill slopes down to the right of the user. One obvious problem is the standard location of the throttle (right extension of handle), which makes it difficult to get an adequate weight shift toward the uphill side of the vehicle. Other factors come into play such as the pack condition of the snow and the bite achieved by the tracked portion of the vehicle and the skis. These factors are combined with the angle of the slope, the weight of the vehicle, and the balance capability and strength of a user. Some of the above-mentioned factors (condition of snow) cannot be predicted by a user until a side-hill maneuver is well underway. With all factors taken into account, the prior art construction of snowmobile handlebars and location of the throttle remains a serious impediment to successful side-hilling in either direction.
The above-described problem is well recognized in the art and snowmobile manufacturers have offered after-market solutions in an attempt to reduce the effects of the problem for users. One of these solutions involves adding a half-hoop grab-handle to the handlebar at a position near the xe2x80x9cTxe2x80x9d portion of the bar. A grab-handle allows a user to get more weight shifted toward the uphill side of the snowmobile by allowing the user to grip a center grab-bar instead of the down-slope-extending end of the stock handlebar. Thereby, a user may lean out further when standing on a running board. A problem with this solution is that a user""s hands are placed much closer together on the handlebar when utilizing a grab-bar. Therefore, a user experiences a significant reduction of balance and leverage-ability to control steering. The above problem is compounded by the location of the throttle (right extension of bar), which prevents a user from using his right hand to grasp the grab-bar when side-hilling. Hence, difficulty of side-hilling wherein the slope angles down to the right of a user is not reduced by addition of a grab-bar.
Some manufactures have equipped handlebars with a dual throttle-control (one at both handlebar-extension ends) so that a user may utilize a grab-bar when side-hilling in either direction and still have a hand on a throttle control. However, a left throttle control is very awkward to use in actual practice, and the balance impediment caused by a close-together placement of a user""s hands as well as a reduction in leverage capability for steering remains a tradeoff.
What is clearly needed is a method and apparatus that would enable a user to get maximum weight-shift toward the upside of a hill during a side-hilling maneuver in either direction without sacrificing balance or steering leverage, and without having to use an additional throttle control or an added grab-bar. Such a method and apparatus would greatly improve a user""s capacity to maneuver a snowmobile or other similar off-road vehicle when side-hilling and when performing a host of other maneuvers.
In a preferred embodiment of the present invention an angularly-adjustable steering system for a vehicle is provided, comprising a steering column connected to a lower steering member for enabling control of steering direction of the vehicle; a handlebar apparatus for enabling user-applied direction for steering the vehicle; and a bar-angling mechanism for enabling angular adjustment of the handlebar apparatus, the bar angling mechanism fixedly adjoined to the handlebar apparatus at one end, and fixedly adjoined to the steering column at the other end, such that a user gripping the handlebar apparatus may position the handlebar apparatus to a desired angle of tilt by virtue of pivotal mechanics of the bar-angling mechanism. The steering system is particularly adaptable to a snowmobile in one preferred embodiment, and to an all-terrain vehicle (ATV).
In one embodiment the bar-angling mechanism utilizes at least one bi-directional, linear locking-device for locking and unlocking the position of the handlebar apparatus. In another the bar-angling mechanism is spring loaded and is unlocked and locked by operating an external control lever.
In another aspect of the invention a mechanism for providing angular adjustment capability to a vehicle steering system is provided comprising an upper mounting-plate fixedly adjoined to a handlebar apparatus; a lower mounting plate fixedly adjoined to a steering column; a pivotal mount for connecting the upper mounting-plate to the lower mounting-plate; at least one spring-retention rod pivotally mounted to the upper-mounting plate and supporting a spring compressed against the lower mounting-plate and against the end of the rod; and at least one locking-unlocking device for freeing or restricting movement of the connected handlebar apparatus along a tilt range. In one embodiment free angular movement of the handlebar apparatus is resisted by spring compression. In another embodiment the locking device is a bi-directional, linear locking-device. The linear locking device may be lever actuated and controlled by an external, user-operated, cable-assisted lever.
In one embodiment at least one linear locking device is adapted for spring retention and is used in place of at least one spring retention rod.
In yet another aspect of the invention a method for adjusting the angular position of a handlebar apparatus connected to a vehicle steering system is provided, comprising the steps of (a) activating an external control to unlock a bar-angling mechanism; (b) tilting a connected handlebar apparatus to a desired position along a vertical range of tilt; and (c) locking the bar-angling mechanism through release-activation of the external control.
In the method, in step (a) and (b), the external control may be a user-operated, cable-assisted lever. The method applicable to snowmobiles and all-terrain vehicles.
In embodiments of the present invention taught in enabling detail below, for the first time a mechanism is provided the art alowing a user of a snowmobile or ATV to efficiently and safely maintain operation on hillsides.